This invention relates to a method for the 3D digitalization of an object with variable surface, in which for determining the 3D coordinates of the surface of the object a plurality of camera pictures of partial surfaces of the object are taken and put together.
A method for the 3D digitalization of an object with a non-variable surface according to the generic part of claim 1 is known from EP 2 144 036 A2. In this method an object with non-variable surface is irradiated with white-light stripes. A camera takes pictures of partial surfaces of the object. The camera can comprise an optical system and a planar sensor, for example a CCD sensor or a CMOS sensor. From the camera pictures, the 3D coordinates of the partial surfaces of the object are determined. The 3D coordinates of the partial surfaces are put together by a matching method.
In EP 2 144 036 various pictures are taken from the object, from which 2D feature points of the object are determined. Subsequently, the 3D coordinates of the 2D feature points are determined. Between the 2D feature points of a picture and the 2D feature points of another picture the 2D point correspondences are determined. A plurality of these 2D point correspondences are selected, and an associated 3D transformation is determined. With reference to the transformed 3D coordinates of the 2D feature points the quality of this 3D transformation is determined, and valid 3D feature points are determined therefrom. For assembling the camera pictures of the object the 3D coordinates of the valid 3D feature points are used.
However, there are also known other matching methods with which the present invention can be carried out, for example the method of the least square errors or other matching methods.
In objects with variable surface, for example in living beings, in particular humans, the problem arises, however, that the camera pictures of the partial surfaces are taken at a time interval from each other, so that the surfaces and partial surfaces can vary between the shots.